Abstract

The theoretical study of off-resonant fifth-order two-dimensional (2D)-Raman spectroscopy is made to analyze the intermolecular dynamics of liquid and solid water. The 2D-Raman spectroscopy is susceptible to the nonlinear anharmonic dynamics and local hydrogen bond structure in water. It is found that the distinct 2D-Raman response appears as the negative signal near the axis. The origin of this negative signal for is from the nonlinear polarizability in the librational motions, whereas that for is attributed to the anharmonic translational motions. It is found that the mechanical anharmonicity and nonlinear polarizability couplings among modes clearly can be observed as the sum- and difference-frequency peaks in the 2D-Raman spectrum (i.e., Fourier transforms of the response). The 2D-Raman spectroscopies of ice Ih and amorphousices, i.e., low density, high density, and very high density amorphousices, are also investigated. It is found that the 2D-Raman spectroscopy is very sensitive to the anisotropy of the structure of ice Ih. The strong hydrogen bond stretching band is seen in the 2D-Raman spectroscopy of the polarization directions parallel to the axis, whereas the contributions of the librational motion can be also seen in the spectrum with the polarization directions parallel to the axis. The 2D-Raman spectroscopy is also found to be also very sensitive to the differences in local hydrogen bond network structures in various amorphous phases.

Received 15 May 2006Accepted 26 June 2006Published online 24 August 2006

Acknowledgments:

The calculations have been carried out by using the supercomputers at Information Technology Center in Nagoya University and at Research Center for Computational Science in Okazaki. The present work was supported by the Grant-in-Aid for Specially Promoted Research (No. 14100100) and the Grant-in-Aid for Scientific Research (No. 16350008).